The legend of Sam Miracle

"Sam Miracle's life is made up of dreams, dreams where he's a courageous, legendary hero instead of a foster kid with two bad arms that can barely move. Sometimes these dreams feel so real, they seem like forgotten memories. And sometimes they make him believe that his arms might come alive again. But Sam is about to discover that the world he knows and the world he imagines are separated by only one thing: time. And that separation is only an illusion. The laws of time can be bent and shifted by people with special magic that allows them to travel through the past, present, and future. But not all of these--time walkers--can be trusted... However, it's an adventurous girl named Glory and two peculiar snakes who show Sam the way through the dark paths of yesterday..."--Amazon.com.